Ashit,
If this is Solaris 10 8/07, you may be running into bug:
6608977 - Can't add device to non-global zone in S10 update 4 (Solaris 10 8/07)
You can tell what version of Solaris you are running from the contents of
/etc/release.
The patches for this bug are:
125914-01 (x86/x64)
127111-03
Thanks Joe for the responses.
I am currently running Solaris 10 10/08 so i assume the bug you mentioned is
already fixed in this release.
$cat /etc/release
Solaris 10 10/08 s10s_u6wos_07b SPARC
Copyright 2008 Sun Microsystems, Inc. All Rights Reserved.